This invention relates to methods for the restoration of intraosseous spaces as well as methods for the reparation of bony defects, fractures and surgically created defects. The invention relates to methods for restoring intraosseous spaces in percutaneous surgical procedures, such as percutaneous vertebroplasty, and in the repair of fractures in procedures such as those requiring screw augmentation, including cannulated screw augmentation.
Percutaneous surgical procedures have come to the forefront of the orthopaedic and neurological surgery fields, in an effort to limit exposure of tissues, reduce operating time, speed up recovery time and minimize patient scarring. Percutaneous vertebroplasty is a procedure by which, currently, acrylic cement, typically polymethylmethacrylate (xe2x80x9cPMMAxe2x80x9d), is injected into the vertebral body by a percutaneous route in order to prevent vertebral body collapse and pain in patients with unhealthy vertebral bodies. Percutaneous injection has been indicated as a means of pain relief and restoration in patients with vertebral hemangiomas, painful vertebral body tumors, as well as painful osteoporosis with loss of height and/or compression fractures of the vertebral body. See, e.g., Gangi, A., et al. Percutaneous Vertebroplasty Guided by a Combination of CT and Fluoroscopy, AJNR 15:83-86, January 1994 (xe2x80x9cGangixe2x80x9d). All references cited in this specification are incorporated herein by reference. Percutaneous injection is also minimally invasive compared to the alternative of exposing the entire soft and hard tissue at the surgical site.
U.S. Pat. Nos. 6,033,411 and 6,019,776 to Preissman, et al. disclose methods for controlled approach to the interior of a vertebral body by inserting a threaded or sharp-pointed stylet and cannula percutaneously through the soft tissue of an organism until abutting the soft tissue; further inserting the stylet into a predetermined location within the hard tissue; ratcheting a pawl mechanism or rotating a camming mechanism to advance the cannula along the stylet to the predetermined location; withdrawing the stylet from the cannula and attaching a source of implantable material for injection of the material into the organism through the cannula. However, these patents do not teach methods of delivering restorative material by percutaneous vertebroplasty in which several doses of material are injected.
Heini, P. F. et al., Percutaneous Transpedicular Vertebroplasty with PMMA: Operative Technique and Early Results: A Prospective Study for the Treatment of Osteoporotic Compression Fractures, Eur. Spine J. (2000) 9:445-450 (xe2x80x9cHeinixe2x80x9d), discusses the use of PMMA for percutaneous vertebroplasty and disclose the surgical practice of using four injections (i.e., injecting four vertebrae unipedicularly or two vertebrae bipedicularly) in one session under local anesthesia. The procedure disclosed, states that within xe2x80x9ctwo minutes into the cement curing, filling is commenced and then the material remains injectable for the following 2 or 3 minutes.xe2x80x9d Heini further cautions that the flow of cement must be monitored carefully for leakage posteriorly into the spinal canal and anteriorly through the nutritional vessels. Heini also teaches that only low-viscosity PMMA is suitable for injection and that the radio-opaqueness of injectable calcium phosphate makes its use technically difficult to achieve.
Deramond, H., et al., Percutaneous Vertebroplasty, Seminars In Musculoskeletal Radiology, Vol.1, No.2, 1997: 285-295 (xe2x80x9cDeramondxe2x80x9d), Chiras, J., et al., Percutaneous Vertebroplasty, J Neuroradiol, 1997, 24, 45-59 (xe2x80x9cChirasxe2x80x9d), Jensen, M. E., et al., Percutaneous Polymethylmethacrylate Vertebroplasty in the Treatment of Osteoporotic Vertebral Body Compression Fractures: Technical Aspects, AJNR 18:1897-1904, November 1997 (xe2x80x9cJensenxe2x80x9d), and Gangi describe the percutaneous injection of PMMA into the vertebral body with the aid of CT and/or fluoroscopic guidance. Prior to injecting the material, each method describes the step of preparing the injectable acrylic cement material. As described by Gangi, in order to prevent distal venous migration, the acrylic cement has to be injected during its pasty polymerization phase (page 84). Further, since the surgeon is required to wait until the material reaches the pasty polymerization phase, xe2x80x9cthe intervention [has] to be performed quickly, because the glue [begins] to thicken after 3 minutes, and any further injections [become] impossible.xe2x80x9d During material injection, the procedure is immediately stopped if an epidural or paravertebral opacification (under strict lateral fluoroscopy) is observed to prevent spinal cord compression. Deramond suggests that a leakage can be avoided by making injections under lateral fluoroscopic control or inserting the needle into the lateral part of the vertebral body. Jensen also teaches that the material should set only if a leak should occur.
In the prior art, if a leak is detected, the operator either stops the procedure altogether, continues with the injection of more material using a different xe2x80x9cbatchxe2x80x9d of material, or allows the material that already has been injected to thicken. Clinically, using a different xe2x80x9cbatchxe2x80x9d of material requires opening another xe2x80x9cbatchxe2x80x9d of material. This is costly and not desirable or practical in the case of standard restorative materials such as PMMA. If the surgeon does not allow the material to set, but rather merely allows it to thicken, which is more often the case, then he is forced to work quickly and often cannot deliver the desired amount prior to all the material""s setting. Forceful injection is required to add additional material prior to the material""s setting. Another problem with procedures of the prior art is that a catheter is rarely used. If the material hardens, it will also harden in the cannula where it would have to be removed for the injection of additional doses. Surgeons are very skeptical about doing this because of the extreme difficulty in reinserting another cannula in the exact place as the one removed.
It is the principle object of this invention to provide methods for the restoration of intraosseous spaces. It is a further object of the invention to provide methods of controlled injection of restorative material into a vertebral body to prevent leakage of that material into the venous space. It is yet another object of the invention to provide minimally invasive techniques for the reparation and restoration of bony structures and to provide minimally invasive techniques for the augmentation of procedures requiring screw fixation.
Additional objects, advantages and novel features of this invention will become apparent to those skilled in the art upon examination of the following descriptions, figures and claims thereof, which are not intended to be limiting.
This invention relates to methods for restoring an intraosseous space comprising the steps of accessing a space, placing in the space a first aliquot of restorative composition, and, after a period of time sufficient for the first aliquot to set, placing in the space a second aliquot of restorative composition. The first aliquot placed into the space to initiate the restorative process can be preselected. There are preferably additional aliquots of restorative composition placed into said space. These additional placements of composition can follow preselected time intervals and be of a preselected amount. The placements within these methods are preferably made using a syringe and catheter via a needle or cannula that is inserted in the intraosseous space. The location of the instrumentation as well as the material in the intraosseous space is easily monitored via fluoroscopy or endoscopy. In one embodiment, the catheter has a distal end and at least one placement orifice disposed proximate to said distal end, said placement orifice being adapted for dispensing the restorative composition radially from the catheter. The space is accessed via drill, knife, or needle.